diff --git a/spacy/tests/pipeline/test_pipe_factories.py b/spacy/tests/pipeline/test_pipe_factories.py
index 2af4b1efb..e1706ffb1 100644
--- a/spacy/tests/pipeline/test_pipe_factories.py
+++ b/spacy/tests/pipeline/test_pipe_factories.py
@@ -451,13 +451,27 @@ def test_pipe_factories_from_source_config():
     assert config["arg"] == "world"
 
 
-def test_pipe_factories_decorator_idempotent():
+class PipeFactoriesIdempotent:
+    def __init__(self, nlp, name):
+        ...
+
+    def __call__(self, doc):
+        ...
+
+
+@pytest.mark.parametrize(
+    "i,func,func2",
+    [
+        (0, lambda nlp, name: lambda doc: doc, lambda doc: doc),
+        (1, PipeFactoriesIdempotent, PipeFactoriesIdempotent(None, None)),
+    ],
+)
+def test_pipe_factories_decorator_idempotent(i, func, func2):
     """Check that decorator can be run multiple times if the function is the
     same. This is especially relevant for live reloading because we don't
     want spaCy to raise an error if a module registering components is reloaded.
     """
-    name = "test_pipe_factories_decorator_idempotent"
-    func = lambda nlp, name: lambda doc: doc
+    name = f"test_pipe_factories_decorator_idempotent_{i}"
     for i in range(5):
         Language.factory(name, func=func)
     nlp = Language()
@@ -466,7 +480,6 @@ def test_pipe_factories_decorator_idempotent():
     # Make sure it also works for component decorator, which creates the
     # factory function
     name2 = f"{name}2"
-    func2 = lambda doc: doc
     for i in range(5):
         Language.component(name2, func=func2)
     nlp = Language()
diff --git a/spacy/util.py b/spacy/util.py
index f55b03db8..aa9bf301e 100644
--- a/spacy/util.py
+++ b/spacy/util.py
@@ -930,6 +930,8 @@ def is_same_func(func1: Callable, func2: Callable) -> bool:
     """
     if not callable(func1) or not callable(func2):
         return False
+    if not hasattr(func1, "__qualname__") or not hasattr(func2, "__qualname__"):
+        return False
     same_name = func1.__qualname__ == func2.__qualname__
     same_file = inspect.getfile(func1) == inspect.getfile(func2)
     same_code = inspect.getsourcelines(func1) == inspect.getsourcelines(func2)